Protein-based materials have attracted a great deal of interest as both bioactive and bioelectronic materials. In addition, it has become increasingly clear over the last decade that control over biological functionality is critical to controlling the interface of biomaterials with living systems. The presentation of protein signals that aid or deter cell adhesion, differentiation, growth, and migration is critical to enhancing wound healing, controlling stem cell behaviors, and synthesizing robust antimicrobial surfaces. It has also been demonstrated that both the microscale and nanoscale spatial arrangement of these factors have a large impact on the elicited biological response, motivating the desire to produce self-assembled nanostructures from these materials, including nanopatterned surfaces and fibrillar tissue engineering matrices.
A number of approaches have also been pursued to develop nanostructured proteins for biosensors and bioelectronics, but none of these devices achieve the ideal combination of transport properties, control of protein orientation, and nano scale spatial control in either two or three dimensions. For example, surface nanopatterning based on the attachment of proteins to chemically inhomogeneous surfaces has been used as one method of promoting focal adhesion formation. Nanoscale topographical patterns of posts or lines have also been prepared by photolithography, but those lithography steps are costly and their ability to pattern on very short length scales is limited. To go beyond two-dimensional nanostructures, electrospun nanofiber scaffolds, self-assembled peptide nanofiber scaffolds, nanocomposites, and collagen fiber matrices have been investigated, but none of these materials produces a regularly ordered nanostructure.
Therefore, there remains a need in the art for protein-based materials, in particular, those can produce well-controlled three-dimensional nanostructures.